Here is the full list of all 40 Dead achievements.
Kill Totem
Do not dodge when fighting Totem
Kill Puppeteer
Never take damage from the clock
Kill Furnace
Kill Eremite first
Kill Eremite and Spectre
Kill Vescile
Never allow Vesicle to heal
Kill Progenitor without exploding
Kill Progenitor
Dead
Kill Migraine
Kill The Silenced
Kill Glass Master
Kill Scourge
Kill Eight Bears
Kill Dying Ember
Never allow Smelter to get the sword
Never take damage when fighting Migraine
Never fire a bullet or explode when fighting Totem
Kill The Silenced within 60 seconds
Kill Scourge without exploding
Never take damage when fighting Glass Master
Kill Eight Bears using only explosions
Only use explosions when killing Dying Ember
Kill Progenitor without moving
Kill Vesicle without leaving the bridge
Ring the bell
Never dodge when fighting Furnace and Smelter
Summon the second ring
Do not dodge when fighting Puppeteer
Kill The Silenced before killing Migraine
Do not destroy any crystals
Never dodge when fighting Glass Master
Kill Eight Bears in Easy Mode
Kill Dying Ember on Easy Mode
Complete DEAD in Easy Mode
Complete DEAD with Boss Rush Mode and One Hit Mode enabled
Complete DEAD with Easy Mode, Boss Rush Mode and One Hit Mode enabled